[Intel-gfx] [PATCH 24/57] drm/i915/gt: Only kick the scheduler on timeslice/preemption change

[Tvrtko Ursulin]

On 01/02/2021 08:56, Chris Wilson wrote:
> Kick the scheduler to allow it to see the timeslice duration change,
> don't peek into execlists.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>   drivers/gpu/drm/i915/gt/sysfs_engines.c | 11 +++++------
>   1 file changed, 5 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/sysfs_engines.c b/drivers/gpu/drm/i915/gt/sysfs_engines.c
> index 57ef5383dd4e..526f8402cfb7 100644
> --- a/drivers/gpu/drm/i915/gt/sysfs_engines.c
> +++ b/drivers/gpu/drm/i915/gt/sysfs_engines.c
> @@ -9,6 +9,7 @@
>   #include "i915_drv.h"
>   #include "intel_engine.h"
>   #include "intel_engine_heartbeat.h"
> +#include "intel_engine_pm.h"
>   #include "sysfs_engines.h"
>   
>   struct kobj_engine {
> @@ -222,9 +223,8 @@ timeslice_store(struct kobject *kobj, struct kobj_attribute *attr,
>   		return -EINVAL;
>   
>   	WRITE_ONCE(engine->props.timeslice_duration_ms, duration);
> -
> -	if (execlists_active(&engine->execlists))
> -		set_timer_ms(&engine->execlists.timer, duration);
> +	if (intel_engine_pm_is_awake(engine))
> +		intel_engine_kick_scheduler(engine);
>   
>   	return count;
>   }
> @@ -326,9 +326,8 @@ preempt_timeout_store(struct kobject *kobj, struct kobj_attribute *attr,
>   		return -EINVAL;
>   
>   	WRITE_ONCE(engine->props.preempt_timeout_ms, timeout);
> -
> -	if (READ_ONCE(engine->execlists.pending[0]))
> -		set_timer_ms(&engine->execlists.preempt, timeout);
> +	if (intel_engine_pm_is_awake(engine))
> +		intel_engine_kick_scheduler(engine);
>   
>   	return count;
>   }
> 

Almost feels like from sysfs layer intel_engine_kick_scheduler should 
dtrt without the need to check intel_engine_pm_is_awake. Even if that 
means having __intel_engine_kick_scheduler for more intimate callers, if 
required.
  But anyway it is no worse than it was.

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Regards,

Tvrtko